﻿NORTH AMERICAN NOTOSTRACA — LINDER 51 



Typo locality. — Honey Lake, Calif. 



Types. — The type specimens (4 9, 1 &) are said to have been lost 

 in the San Francisco fire. 



Remarks. — Holmes' description is very good for its time, but 

 naturally it does not mention the number of abdominal leg-bearing 

 rings or the total number of rings. In these respects, there are two 

 well demarcated groups within the genus, and these totals seem to be 

 essential for a proper identification. Perhaps both were low, because 

 he reports only 4 rings exposed behind the carapace; but we cannot 

 be certain of this. Equivalent totals in L. lynchi var. echinatus are 

 high even though as few as 7 rings are exposed. Only 12 specimens 

 are knowm of the latter form, and only 5 of L. lemmoni. So few speci- 

 mens cannot be expected to show a full range of variation; thus, it 

 is possible that L. lemmoni may fall in within the upper limits of 

 variation in this respect. And we must not forget that, in general, 

 the munber of exposed rings is sho^vQ to be an unreliable character, 

 so its value as an indicator of the number of rings is very uncertain. 



Other characters do not give clear indications, either. The nuchal 

 organ is "located considerably behind the posterior margins of the 

 eyes." Perhaps we have a condition here similar to that in L. lynchi 

 and L. lynchi var. echinatus, but a precise comparison is impossible 

 because Holmes does not mention the place of the organ in relation 

 to the eye-tubercles, only to the eyes. 



The very long caudal filaments present a character of doubtful 

 significance. In each large lot of Lepidurus there is considerable 

 variation in the length of these appendages. 



The lateral spines on the carapace look quite conspicuous on Holmes' 

 figure. Similar spines, or larger still, are found in L. lynchi var. 

 echinatus, whereas in aU other notostracans I have seen the correspond- 

 ing structures are minute and inconspicuous. But echinatus differs 

 clearly from L. lemmoni by its very shallow posterior emargination 

 of the carapace as weU as by the structure of its legs, and so an 

 identification with this form seems higldy improbable. 



To sum up, the characters given for L. lemmoni cannot be regarded 

 as sufficient for a proper identification. In my opinion, we had 

 better not keep the species on record. 



It can be abandoned without much trouble, because, as far as I 

 can see, it has been recorded only once since its establishment, and in 

 this case there is undoubtedly an error of identification. Coopey 

 (1946) refers some specimens from Oregon to this species, though 

 with the express reservation that they are only provisionally identified. 

 JMost kindly, he has given me the opportunity of examining 3 speci- 

 mens from Ilocky Pomt Pond, Klamath County. I find them to 

 belong to L. couesii. The telson (without supra-anal plate) is short 

 and broad, and on the conspicuous keel of the supra-anal plate there 



